#!/usr/bin/env python

import sys
import ROOT
ROOT.gROOT.SetBatch()
from DataFormats.FWLite import Events, Handle,Runs
handle=Handle('GenRunInfoProduct')
label=("generator")
if len(sys.argv) <2:
# print str(sys.stdin.readlines())[2:-4]
 runs = Runs(str(sys.stdin.readlines())[2:-4])
else:
 runs = Runs (sys.argv[1])
# print sys.argv[1]
runs.getByLabel(label,handle)
geninfo=handle.product()
print geninfo.crossSection()
